ABSTRACT Locke’s Letter on Tolerance has been a controversial issue since the seventeenth century: its defense of tolerance compromises restricting atheists and Catholics, which would attain religious freedom, one of the highest values of liberal theory. Taking this issue as its central, the purpose of this article is to think about this tension in Locke’s political thinking. In order to collaborate with this debate, the text is divided in two parts: in the first one, the various meanings of what Locke (...) understands by atheist will be presented in his different political texts; in the second, we will analyze the importance of religion in Lockean political thought. (shrink)